Anchor alarm device



Oct. 15, 1957 T. R. PARKER 2,810,120

ANCHOR ALARM DEVICE Filed Dec. 2, 1955 Y 2 Sheets-Sheet 1 HTTORI EY$United States Patent ANCHOR ALARM DEVICE Thomas R. Parker, Durham, N. C.

Application December 2, 1955, Serial No. 550,592

6 Claims. (Cl. 340-29) My invention relates to a drift alarm device formarine vessels and the principal object is to provide a device whichwill give audible or visual warning that an anchored vessel is draggingits anchor or drifting from its anchored position but will not give suchwarning if the vessel is only moving about its anchorage circle when theanchor is holding.

The device is particularly useful for small craft such as boats, barges,seaplanes and the like (which I refer to herein as vessels) on which itis not usual to keep a night watch. When such vessels are anchored it isnot infrequent that high wind, current conditions, fouling of the anchorby the anchor line, etc. will cause the anchor to lose its hold on thebottom and the vessel will drift in the direction of the wind orcurrent. When this occurs the anchor will drag and the dragging anchorwill tend to hold the bow of the vessel into the wind or current as theboat drifts. It is drifting of this charac ter which will activate thedrift alarm device.

An anchored vessel will also move in an approximate circle about itsanchor when the anchor is holding, due to changes in current, tide andwind condition and it is a feature of my alarm device that such normalmovement of the vessel can take place without activation of the alarm.

I have illustrated my invention in preferred form in the accompanyingdrawings wherein:

Fig. 1 shows in full lines a vessel at anchor with my alarm devicemounted on the bow. In dotted line the vessel is shown dragging itsanchor.

Fig. 2 illustrates in full lines the vessel at anchor with the anchorholding and in dotted lines shows the vessel as it has moved about itsanchorage circle.

Fig. 3 illustrates in dotted lines the vessel at anchor and in fulllines the position of the vessel after it has dragged its anchor.

Fig. 4 is a sectional elevation of the alarm and alarm actuating andmounting mechanism.

Fig. 5 is a plan view of Fig. 4.

Fig. 6 is a section taken on the line 66 of Fig. 4.

Fig. 7 is a diagram of the electrical circuit of the alarm.

Referring now to Figures 4 to 7 the alarm device is mounted in arectangular box B which is attached to the bow of the vessel A by meansof screws or bolts extending through apertures 8. The cover of the boxis readily removable to permit inspection and adjustment of the alarm.

The alarm comprises a rustless tubular member 9 extending through theforward end of the box and pro jecting over the bow of the vessel. Thetube 9 is mounted on the base of the box B by means of a clamp 10adjacent the forward wall of the box. The clamp has a longitudinal bore11 extending at an angle to the horizontal and the tube 9 is secured inthis bore of the clamp by means of set screw 12. The rear end of thetube is supported by a brace 13 which is secured to the bottom of thebox and it will be observed that the tube 9 has a slight downwardinclination from rear to front.

A solid rustless metal rod 14 is slidably mounted in the tube 9 andextends beyond the ends of the tube both at the forward and rear endsthereof. Rearward movement of the rod 14 is limited by engagement of thepin 15 with the forward end of the tube 9.

A spring 16 is attached to the rear end of the rod 9 and the rear end ofthe spring 16 is attached to a movable cross-bar 17 carried by screws18. Springs 19 surrounding screw members 18 bear against the cross-bar17 and the rear end of the box B and urge the cross-bar forward and theposition of the cross-bar can be adjusted forwardly and rearwardly bymeans of the screws 18 in order to adjust the tension of the spring 16.

A metallic collar member 20 is secured to the rear end of the rod 14 bymeans of a set screw and this collar member is electrically connected bymeans of a wire 21 to a terminal member 22 extending through the wall ofthe box 8.. Wire 23 is connected at one end to the terminal 22 and atthe other end to the terminal of an electrical bell or light indicatedas a whole by the reference character C. A tubular insulating sleeve 24is mounted on the rear end of the tube 9 and to this sleeve anelectrical contact member 25 is secured by means of screws, one of thescrews constituting an electrical terminal. This latter terminal isconnected to one side of a switch D by means of a wire 26 and the otherside of the switch is connected by wire 27 to terminal member 28 whichis connected by wire 29 to one terminal of the battery 36. The otherterminal of the battery 36 is connected to the hell or lamp C as shownin Figure 7.

Forward movement of the rod 14 will carry the collar 20 forwardly intocontact with contact member 25 and when the switch D is in closedposition, will close the circuit which will cause an audible or visiblesignal from the hell or lamp C.

A plummet line 31 is connected to the forward end of the rod 14 and theopposite end of the plummet line 31 is connected to a plummet 32. Theplummet is preferably made of a heavy brass rod or some otherrust-resisting metal and the opposite ends of the rod are bent at rightangles to the central portion in the manner illustrated in the drawings,the bent arms of the plummet lying in the same general plane.

I have found that a plummet of this shape works quite successfully anddoes not dig into the bottom but it will be understood that the plummetcan be of any shape so long as it does not dig into the bottom or rollor slide with the current.

The operation of the alarm device is as follows:

When the vessel A has been anchored in the usual manner as illustratedin full lines in Fig. l by means of the anchor 33 attached to the bow ofthe vessel by anchor line 34, the plummet line is attached to theforward end of the rod 14 and the plummet is dropped over the side tolie on the seat bottom below the bow of the vessel. The switch D is thenclosed. The plummet line should be of sufficient length to allow a fewfeet of slack line to lie on the bottom.

If now the anchor should become fouled by the anchor line or lose itshold on the bottom, the vessel will move away from its anchorage and thepull of the dragging anchor on the bow will tend to turn the bow of thevessel into the wind or into the current. This movement of the vesselwill also take the slack out of the plummet line and cause the plummetto drag along the sea bottom. When this occurs, the plummet line willexert a forward pull on the rod 14 and when this pull has becomesufiicient to overcome the tension of the spring 16 and the friction ofthe rod within the tube, the rod will move forwardly in the tube 9bringing the metallic collar 20 into contact with the contact member 25,thus closing the 3 circuit to ring the bell or light the lamp C, thusindicating to those on board the vessel that the vessel is drifting withthe anchor dragging.

It is to be noted that since the dragging anchor will tend to keep thebow of the boat into the wind or current,

the plummet line in dragging the plummet will also stream out in thegeneral direction of the anchor line in a vertical plane generallyparallel to the fore and aft axis of the boat so that the pull on therod 14 will be forward, in the general direction of the anchor line. Thegeneral slanting of the tube 9 and rod 14 will tend to reduce the anglebetween the rod 14 and the plummet line and I have found that in generalpractice it is desirable to arrange the parts so that any position ofthe plummet line within an arc of about 30 forward of the vessel willexert suflicient pull to cause the rod 14 to move forward when theplummet is dragging. In this connection it is to be observed that it isimportant that the plummet lie on the sea bottom rather than beingsuspended above the bottom for if the plummet is suspended above thebottom, it will not exert sufiicient drag by movement through the waterto exert a pull on the rod 14.

It is obviously not desirable that the alarm be actuated when the vesselis moving in its anchorage circle with the anchor holding. If thisoccurs the angle between the plummet line, attached to the plummetbeneath the bow, and the rod 14 will be such that the pull on theplummet line is very nearly at right angles to the axis of the rod. Whenthis occurs the tension of the spring 16 and the friction between therod 14 and tube 9 is such that the lateral pull of the plummet line onthe rod will not cause it to move. This position of the plummet andplummet line is indicated in dotted lines in Fig. 2 where it will beobserved that the plummet line is substantially at right angles to therod 14. From the foregoing it will be understood that the vessel canmove freely in its anchorage circle without actuating the alarm for theonly effect on the plummet is to drag it in a circle on the bottomcorresponding to the circle described by the bow of the vessel in movingabout the anchor, and this will not exert a pull on the plummet linewhich will move the rod 14 forward.

My improved alarm device may be installed on the bow of any small craftin a relatively short time. It can be adjusted by the turning of thescrews 18 to increase or decrease the tension of the spring 16 to allowfor difference in pull by the plummet due to different types ofanchorage bottoms and will make the anchoring of small vessels very muchsafer. When the vessel is anchored with persons aboard, it is normallypreferable that the alarm device be audible. However, when the vessel isanchored in a yacht basin, a warning light is preferable if no one isaboard to warn attendants of the outbasin that the vessel may bedragging its anchor.

I claim:

1. A drift alarm device for vessels comprising an alarm actuatingmember, means for mounting said member on a vessel providing for foreand aft movement thereof while providing against lateral movementthereof, yielding means for normally holding said member in nonalarmposition, a warning signal actuated by movement of said member from itsnormal position, a plummet line secured to said member and a plummetsecured to said line and adapted to lie on the sea bottom when thevessel is at rest.

2. A drift alarm device for vessels comprising an alarm actuatingmember, means for mounting said member on a vessel providing for foreand aft movement thereof, yielding means for normally holding saidmember in nonalarm position, a warning signal actuated by movement ofsaid member from its normal position, a plummet line secured to saidmember and a plummet secured to said line and adapted to lie on the seabottom when the vessel is at rest, the mounting means for said alarmactuated member being so constructed and arranged as to permit movementof the member only in response to a forward pull by the plummet line.

3. A drift alarm device for vessels at anchor comprising an alarmactuating member, means for mounting said member on a vessel providingfor fore and aft movement thereof, yielding means for normally holdingsaid member in non-alarm position, a warning signal actuated by movementof said member from its normal position, a plummet line secured to saidmember and a plummet secured to said line and adapted to lie on the seabottom when the vessel is at rest, the mounting means for said alarmactuated member being so constructed and arranged as to permit movementof the member only in response to a pull by the plummet line in thegeneral direction of the anchor line.

4. A drift alarm device for vessels comprising an alarm actuating rod,means for mounting said rod on the vessel providing for fore and aftlengthwise movement thereof,

' while providing against lateral movement thereof, yielding means fornormally holding said rod in non-alarm position, a warning signalactuated by forward movement of said rod from its normal position, aplummet line secured to said rod and a plummet secured to said line andadapted to lie on the sea bottom when the vessel is at rest.

5. A drift alarm device for vessels comprising an alarm actuating rod,means for mounting said rod on the vessel providing for fore and aftlengthwise movement thereof, yielding means for normally holding saidrod in nonalarm position, a warning signal actuated by forward movementof the rod from its normal position, a plummet line secured to the rodand a plummet secured to said line and adapted to lie on the sea bottomwhen the vessel is at rest, the mounting means for said rod being soconstructed and arranged as to permit movement of the rod only inresponse to a forward pull by the plummet line.

6. A drift alarm device for vessels at anchor comprising an alarmactuating rod, means for mounting said rod on a vessel providing forfore and aft lengthwise movement thereof, yielding means for normallyholding said rod in non-alarm position, a warning signal actuated byforward movement of said rod from its normal position, a plummet linesecured to said rod and a plummet secured to said line and adapted tolie on the sea bottom when the vessel is at rest, the mounting means forsaid rod being so constructed and arranged as to permit movement of therod only in response to a pull by the plummet line in the generaldirection of the anchor line.

References Cited in the file of this patent UNITED STATES PATENTS

